Many occupations including, but not limited to, firefighting, emergency response, search and rescue, and military service, may require exposure to extreme heat and/or flames. To avoid being injured while working in such conditions, individuals typically wear protective garments constructed of special flame resistant materials designed to protect them from both heat and flames. These protective garments include, for example, garments worn by firefighters, which are commonly referred to in the industry as turnout gear. Turnout gear can include various garments including coveralls, trousers, and jackets. These garments typically include several layers of material such as an outer shell that protects the wearer from flames, a moisture barrier that prevents the ingress of water into the garment, and a thermal barrier that insulates the wearer from extreme heat. Other types of protective garments are worn by individuals such as petrochemical workers, electrical workers, those engaged in military service, and others who require protection from extreme heat and/or flames.
Some individuals including, but not limited to, emergency personnel such as firefighters and other first responders, are not only exposed to extreme heat or flames, but are also exposed to water. In those instances it would be desirable for a flame resistant fabric to also have water repellant properties. Thus, turnout gear and other protective garments may include woven fabrics formed of one or more types of flame resistant fibers, and the fabrics may also have water repellant properties.
Protective garments must withstand flame, excessive heat, and abrasion, and in many instances they are constructed of a flame resistant material that is both strong and durable. These protective fabrics are expensive, so durability of the fabrics is important. Abrasion refers to the wearing away of any part of a material by rubbing against another surface. While flame resistant fibers will retain their flame resistance even if the fabric becomes abraded, a protective fabric that becomes abraded may lose other protective properties such as water repellency. An abraded garment may not provide the protection needed by a firefighter, emergency responder, or other individual. Therefore, if a protective garment becomes abraded, that garment must be replaced. Garments having increased abrasion resistance would need to be replaced less frequently than conventional protective garments. A fabric's resistance to abrasion can be measured by various test methodologies and equipment such as the test procedures described by ASTM standards D3886 and D3884.
Many protective fabrics, including those using ring spun yarns, filament yarns, or combinations thereof can have a tendency to pill. “Pills” are relatively small balls of entangled fibers that can form on the surface of a protective fabric. The pills are held to the surface of the protective fabric by one or more fibers comprising the fabric. While most fabrics pill, the protective fabrics of the present invention are made of strong fibers which hold onto the pills more tightly than many other fibers. Thus, pills that form on these protective fabrics tend to build up on the fabrics. Such pills can accumulate over time or otherwise increase in number on the surface of the fabric causing an otherwise smooth surface to appear worn or in extreme cases unsightly. In some instances, the unsightly appearance of a protective fabric may cause the associated garment to be considered inferior in quality and may discourage a user from using the garment. In many instances, the garment may be replaced prematurely even though the fabric of the garment can still provide suitable protection for the user. A fabric's resistance to pilling can be measured by various test methodologies and equipment, such as a random tumble pilling tester and the test procedures described by ASTM standard D3512.
Conventional techniques to reduce the tendency of fabrics to pill use particular yarns with mechanical twisting of the yarns, such as air jet spun yarns. However, some fibers, including some fibers used in the fabrics of the present invention, cannot be spun by air jets. Furthermore, protective garments made from air jet spun yarns can still be prone to pilling since entangled fibers remain and can form pills on the surface of such fabrics.
It is known in the art to treat fabrics with finishes where the finishes impart a particularly useful property to the fabric. For example, some prior art finishes are water repellant finishes that include an alkylfluoropolymer and other optional additives such as a blocked isocyanate crosslinker, paraffinic waxes, and the like. Other prior art finishes include a moisture management finish which includes softeners, permanent press resins and hydrophilic polymers to impart fabric and fiber hydrophilicity. In either case, fabrics exposed to rigorous physical abrasion tend to show yarn breakage, formation of pills, or both depending on the exact construction and fiber blend used in the fabric.
Prior art finish compositions may also provide some resistance to abrasion and/or pilling. As an example, a composition including a wetting agent, one or more fluoropolymers, a wax fluorochemical extender/water repellant, a melamine formaldehyde resin, and a crosslinking agent has been used. This finish composition was developed and applied to fabrics to impart water repellency that was more durable than the water repellency imparted by previously known formulations. This finish imparts some resistance to abrasion compared to untreated fabrics, but fabrics treated with this finish are still fairly easily abraded. For example, these fabrics only withstand about 500 Taber abrasion cycles before a first thread break when tested in accordance with ASTM D3884, using H-18 wheels and a 500 g load on each wheel.
There remains a need for fabrics and protective garments with improved resistance to surface abrasion and/or pilling.
Accordingly, it is desirable to provide a finish composition capable of imparting such improved resistance to abrasion and/or pilling to a variety of fabrics. It is further desirable to provide flame resistant fabrics and protective garments with improved surface abrasion and/or pilling resistance. Finally, it is desirable to provide flame resistant and water repellant fabrics and protective garments with improved surface abrasion and/or pilling resistance.